DESIGN OF MOLTEN SALT SHELLS FOR USE IN ENERGY STORAGE AT SOLAR POWER PLANTS

Abstract

Design of a steel tank for the storage of excess energy from thermal solar power plants using molten salts (MS) at 580°C is presented. Energy can be stored up to a week in large containers to generate eight hours of electricity for use at night or to reduce weather related fluctuation at solar thermal energy plants. Our research supported by Office of Naval Research (ONR) presents a detailed design of a cylindrical shell for the storage of high temperature molten salts. The storage shell consists of an inner stainless steel layer designed to resist corrosion and an external steel structural layer to contain the large pressures resulting from the molten salt. The cylindrical tank is 54 feet (16.459 meters) high and has an 80 feet (48.768 meters) diameter, with the salt level at a height of 42 feet (12.802 meters). Given the heat of the molten salt and the size of the tank, the design includes a flat shell cover supported on stainless steel columns and a semispherical utility access dome at the center. Considerations are made for the reduction of strength of steel at elevated temperatures. Layers of external insulation materials are used to reduce heat loss in the storage shell. The design presents a posttensioned concrete foundation analysis for the storage tank, which sits on a layer of sand to allow for thermal expansion.